Optionally, specify whether the group should be automatically
added to new users.
Optionally, specify whether the group should be added to existing
users.
Note: Adding the distribution group to existing users is a one-time
setting for this instance only. When you save the distribution group, all users
in the system are added. The next time you view this page, the
Assign to existing users
option is available as more users may have been added to the system.